Deadly MERS Virus Spreads from Camels to People Only Rarely

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Many camels in Saudi Arabia have been infected with the virus
that causes Middle East respiratory syndrome (MERS), but the
virus rarely spreads from the animals to people, a new study
says. The MERS virus first appeared in 2012 and causes a
respiratory illness that has killed 30 percent of the people
infected with it, but it's not well understood.

In the new study, researchers tested blood from 45 people who
were exposed to camels
in Saudi Arabia, including 12 people who had direct contact
with a herd of dromedary (one hump) camels while some of the
animals were infected with MERS. These 12 participants had
repeated contact with the infected camels for more than a month.
For instance, they fed and groomed the camels and, in some cases,
drank milk from the infected animals. The researchers also
analyzed blood from 146 people who lived in the same region but
who did not work with camels.

The researchers concluded that the MERS virus "was not highly
transmissible from dromedaries to humans with various levels of
exposure to this infected dromedary
herd."

Still, the researchers stressed that, although rare, it's still
possible for camels to transmit MERS to humans. It may be more
common for the virus to spread from camels to people "in other
settings in which humans are exposed over sustained periods to
animals among which virus prevalence is higher," the researchers
wrote in their findings.

In fact, a study published last June provided strong evidence
that a 44-year-old man from Saudi Arabia
contracted MERS from one of his camels. Researchers found
that the man and his camel were infected with a genetically
identical strain of the MERS virus. About a week before the man
became ill, he applied a medication to the nose of the infected
camel.

In the new study, the researchers wrote that the situation with
MERS in camels is like that of bird flu (H5N1) in poultry markets
in Asia: Although the virus is common in animals, human infection
is rare, and can seem random.

Future studies on how the MERS virus spreads from camels to
humans should examine whether some people are more susceptible
than others to the infection, the researchers said.

The
study, which was conducted by researchers at King Faisal
University in Saudi Arabia, will be published in the April issue
of the journal Emerging Infectious Diseases.